Question

There are five numbers 9, 11, x, 17, 19. The average of these five number is equal to the value of x. What is the average of the numbers if one more number 20 is added?
1. 15
2. 18
3. 8
4. 19
5. 12

Answer 1

Correct Answer - Option 1 : 15

Formula used: 

Average = (Sum of value of all the numbers)/(Total numbers)

Solution:

Average of five numbers = x 

⇒ (9 + 11 + x + 17 + 19)/5 = x

⇒ 56 + x = 5x

⇒ 4x = 56

⇒ x = 14

Now, the average of the numbers when 20 is added

⇒ Average = (9 + 11 + 14 + 17 + 19 + 20)/6 = 90/6 = 15

∴ Average of the numbers is 15